Limit stop for gun mounts



Jan. I, 1946.

F. C. EASTMAN LIMIT STOP FOR GUN MOUNTS 2 Sheets-Sheet 1 Filed March 23,1944 Jan. 1, 1946.

F. C. EASTMAN LIMIT STOP FOR GUN MOUNTS Filed March 25, 1944 2Sheets-Sheet 2 [nuenior Fredfaqzman Patented Jan. 1, 1946 LIMIT STOP FORGUN MOUNTS Fred C. Eastman, Marblehead, Mass., assignor to United ShoeMachinery Corporation, Flemington, N. J a corporation of New JerseyApplication March 23, 1944, Serial No. 527,854

4 Claims.

This invention relates to means for limiting the extent of angularmovement of devices and is herein illustrated as applied to a gun mounta swinging movement of which is effected by a rotatable driven member.

When guns are supported for movement so that the gunner may train themon a target and are mounted so as to project through an opening in anenclosure such, for example, as through a fixed opening in an airplane,some means must be provided to limit the extent of their swingingmovement in order to prevent the guns from damaging the plane as bycontact with the frame of the opening. The necessity for such limitationof movement becomes increasingly more important as larger and largerguns are being thus used in view of the relatively light structure ofthe so-called skin of the plane. It is evident, too, that, when theswinging movement of the gun is produced by a power-driven member, theuse of an ordinary bumper stop might well be ineifective in case of anaccident such that the power drive is still effective after contact ofthe gun with the sides of, or the frame around, the opening.

An object of the invention is to provide an improved limit stop forpower-operated movable members which shall also be effective to brakethe power-driven member which causes the movement, thus overcoming boththe inertia of the movable member and the force of the power drive.

A feature of the invention resides in the employment of brakes movablewith the member to be stopped and positioned for engagement with thepower-driven member which causes the movement so that they also act asstops. In the illustrated arrangement, the power-driven member is arotatable pinion having a grooved portion, and the limit stop is anarcuate brake member, wedge shaped in cross-section, which is positionedfor engagement with the grooved portion as a bumper and in the groove ofsaid driven member as a brake.

These and other features of the invention will best be understood from aconsideration of the following specification taken in connection withthe accompanying drawings, in which Fig. 1 is an angular view of a gun,mounted for swinging movement in azimuth as well as in elevatign, towhich the novel stops have been applie Fig. 2 is a detail view, on alarger scale and partly in section, showing one of the limit stops inengagement with the grooved portion of the power-driven member;

Fig. 3 is a fragmentary view of the parts shown in Fig. 2 and taken atright angles thereto;

Fig. 4 is a diagrammatic view, on a larger scale, showing one of themotor drives and the stops associated therewith; and

Fig. 5 is a detail view, on the scale of Fig. 4, looking at the end ofone stop and showing how it is supported on a driven segment.

A gun It! is arranged for movement in elevation by being pivoted in theside frames I4 and 15 of a swingable gun mount or yoke which, in turn,is adapted to be turned about a vertical axis so that the gun may betrained in azimuth. The gun trunnion on the near side (not shown)supports a plate l2 having a stud [3 received in a bearing carried by aplate l5 which slides horizontally into a groove formed in the sideframe 14 and is clamped there. The gun trunnion on the far side (notshown) supports a segment gear l8 which is bolted to the gun and has asimilar stud and bearing connection to the side frame It. 'The yoke iscompleted by top and bottom. cross members 20 and 22. Of these, thecross. member 20 is pivoted to the supporting structure in which the gunis mounted, by a top bearing 24, while the lower cross member 22 isreceived in bearings 25 above a segment gear 26 secured to a cross beam28 representing part of the structure in which the gun is mounted.To-and-fro movement of the gun in azimuth is efiected by a powerdrivenpinion 30 meshing with the segment gear 26 and having rotatable with it,and secured to or integral with it, a cylindrical, pulley-like portion32 provided with a tapered groove 34 (Fig. 3)

On the segment gear 26 (Fig. 1), are fastened elongated limit stops 3Band 38 which are spaced by a distance representing the permissible swingof the gun mount in azimuth. Each of these comprises a casing 40 (Fig.2) having a flange 42 carrying dowel pins 44 and a clamp screw 46 tosecure the stop to the segment. In this casing there is a plunger 50provided with an arcuate portion 52 the edge of which is tapered at 54(Fig. 3) to fit the groove 34 of the driven member and thereby to act asa brake as well as a stop. A loaded spring 56 is compressed in thecasing 40 behind the plunger 50, and the limit of outward movement ofthe plunger is determined by a stem 58 having a stop nut 60. Tilting ofthe gun in elevation is effected by a driven pinion 64 meshing with thesegment gear 18 on the gun. Associated with the grooved portion 65 ofthis pinion and mounted on the segment gear l8, there are limit StOps 66and 68, the construction of which is identical with those shown in Fig.2. At the junction between the plunger 50 and the arcuate portion 52 ofeach stop 36, 38, 66 and68, are wings 61 joined at one end and providedwith a notch 69 (Fig. slidably engaging the edge of its associatedflange 42 to hold the elongated arcuate' portions in alignment with andready to enter the groove in the pulley-like portion of its associatedpinion 3D, 64.

One method of driving these pinions 30 and 64 is illustrateddiagrammatically in Fig. 4 wherein there are shown the connections forthe motor which drives the pinion 30. This motor, mounted on a casing 12(Fig. 1) attached to the side frame M, has a worm-and-gear connection 14to a jack shaft 16 which has a similar connection 78 to a vertical shaft80. On the lower end of thisshaft 80 is the pinion 30 meshing with the,teeth of the segmental gear 26. If desired, the control of the motor 10and of the corresponding motor (not shown) which drives the pinion 64may be effected from a distance with the assistance of Selsyntransformers '82 and 84 which may be associated with a remote-controlsystem of the type disclosed in the patent to Hewlett et 'al. No.1,626,824, granted May 3, 1927, or they may be connected in any otherdesired fashion.

In the operation of the drive, it will be seen that, when a swingingmember reaches the limit of desired movement, the arcuate portion 52' ofa limit stop will enter the groove 34 of the member 32 which is attachedto the driving pinion 30 and stop the movement. Inasmuch as this arcuatemember is tapered, it will set up a very considerable braking frictionwith that member and quickly stall the driving motor associated with it.Since the arcuate braking member 52 is resiliently supported in itscasing 40, there is an opportunity for the braking member to yield. Atthesame time, however, the greater the yield of that member, the greaterwill be the compression of its spring 56 and hence the greater will bethe braking force set up, and there will be little tendency to cause thelimit stops to be broken from the segment gears on which they aremounted.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In combination, a swingable support having a gear segment, arotatable driven pinion meshing with the segment on said support, saiddriven pinion having a grooved portion, and a stop movable with saidswingable support and positioned to engage the groove in said drivenpinion to brake it and then positively to stop the rotation of thesupport. I

2.- In combination, a swingable support, a rotatable driven member forswinging said support, said driven member having a grooved portion, anelongated stop movable with said swingable support, and means forholding said stop in position to engage the groove in said driven memberto brake the rotation thereof.

3. In combination, a support for an article, said support beingswingable about an axis, a driven member rotatable about a parallel axisand having a driving connection to said support to swing it, said drivenmember having a portion provided with a tapered groove, and a stopcarried by said swingable support and having a tapered arcuate memberfor engagement in said groove to brake the rotation thereof and thenpositively to stop thesupport at its limit of swinging movement.

4. In combination, a swingable support, a rotatable driven memberconnected to said support to swing it, said driven member having aportion provided with a tapered groove, a stop movable with saidswingable support and having a tapered arcuate member for engagement insaid groove to brake the rotation thereof at the limit of movement ofthe support, yielding means supporting said arcuate member on said stop,and slidably interengaging parts to hold said arcuate member alined withthe groove of said driven member.

FRED C. EASTMAN.

